Reflection of Sound (Physics)

[@abdul-majeedyakubu9813]

Q1. Yes. The laws of reflection of sound are. 1. The incident angle is equal to the reflected angle. 2. The incident ray the reflected ray and the normal ray all lie on the same plane. Q2 Because the room is small. Q3. Distance=speed X time. First echo distance. 2d=340m/s X 0.3s 2d=102 d =51m Second echo distance 2d=340m/s X 0.5 2d=170 d=85m. Total distance=51m + 85m Total distance=136m

[@BlastyaBihan]

i think second echo should be 4d becoz it is coming to us back going and coming back to us once again......Prove me wrong...

[@SrijitaSahaOfficial]

​@@BlastyaBihanno. They are 2 different echosm

[@clashbaba2398]

Sir I'm glad to tell you that I pass my science exam with 78/80 and 79/80 in maths!! Just because of your constant efforts! Thank you sir!

[@ManochaAcademy]

Wow! Congratulations!! Excellent marks in Science and Maths :) Which class are you in?

[@mayadubey8020]

6th ig 🤣

[@AlAmin-ly9nz]

😂🎉🎉🎉🎉​@@mayadubey8020

[@zunairarashed1059]

1. Yes, it does. The laws are stated below 1st law: the incident angle of sound= reflected angle of sound. 2nd law: the incident sound, normal and the reflected sound lie on the same plane 2. Because of insufficient distance echoes can't be heard in small room. We can differenciate between two sound if the time interval between two sounds is 0.1 second. But in a small distance, the sound reflected takes time less than 0.1 sedond. For this we can't differenciate between two sound and can't hear echoes in a small room. 3. Here, for first hill, V= 340 m/s T= 0.3 seconds 2d= vt Or, 2d= 340× 0.3 Or, 2d= 102 Or, d= 102/ 2 Or, d= 51 Here, for second hill, V= 340 m/s T= 0.5 seconds 2d= vt Or, 2d= 340×0.5 Or, 2d= 170 Or, d= 170/ 2 Or, d= 85 Therefore, total= (85+51) = 136 [ Ans ]

[@mathangiaditya4289]

1 st question answer : Yes . Angle of incidence is equal to angle of reflection . 2 nd que answer : Because there are a few good absorbers in our room to absorb sound like , curtains . 3 rd que answer : 1 ; distance = speed * time 2d = 340 m/s * 0.3 2d = 102 m d = 102 / 2 = 51 m 2 ; 2d = 340 * 0.5 2d = 170 d = 170/2 d = 85 m So, 51 + 85 = 136 metres is the distance between the two hills .

[@mathangiaditya4289]

One more law of light , they all are on the same plane .

[@balkimuzam9217]

Is the answers correct

[@mathangiaditya4289]

@@ashishkalra9661 No , check or hear the video again !

[@ashishkalra9661]

@@mathangiaditya4289 Oh, I got it now. Thankyou!

[@mathangiaditya4289]

@@ashishkalra9661 You're Welcome 😊

[@m.vinayagamjeevath2750]

Q01. Yes The laws of reflection are : 1.The incident ray , the normal drawn at the point of incidence and the reflected ray all lie on the same plane. 2.The angle of incidence is equal to the angle of reflection. Q02. We cannot hear echoes in a small room because the persistence of sound of human ear is 0.1 seconds . In a small room, since the distance travelled by the sound wave is less it is reflected back and reaches the human ear within 0.1 seconds. Thus , the reflected sound cannot be heard distinctly and it's not an echo. Q03. Distance=speed X time. First echo distance. 2d=340m/s X 0.3s 2d=102 d =51m Second echo distance 2d=340m/s X 0.5 2d=170 d=85m. Total distance=51m + 85m Total distance=136m

[@sirpi3940]

Hw answers: 1 i) angle of incidence is equal to the angle of reflection i= r ii) Incident ray, normal and reflected ray all lie in the same plane 2) we cannot hear echoes in a small room because the size of reflector must be large 3) distance between the two hills is 136m Lovely session ever seen 😍

[@SrijitaSahaOfficial]

1. Yes, it does. The laws of reflection are: i. The incident ray is equal to the reflected ray. ii. The normal, incident ray, reflected ray drawn at the point of incidence lie on the same plane. 2. In small rooms, The distance between dource and reflecting surface is not 17m but smaller than that. Due to which echo is not heard in these small places. 3. 1st echo: T=0.3s D=2d S≈340m/s 340=2d×10/3 D=51 m 2nd echo, D=2d T=0.5s S≈340 m/s 340=2d×10/5 D=85 m Total distance =51+85 =136 m

[@sourare8206]

Your answers are smart

[@SrijitaSahaOfficial]

@sourare8206 thanks mate

[@powerofmind6253]

1.yes! Why not sound also obey the law of reflection because sound also have same angle of incident and reflected sound having same angle and another on same plane. 2.we cannot hear sound in small room due to small distance between source and reflecting surface i.e less than 17m or may be curtains and dull surfaces which absorb sound energy. 3.As we know that. S=v∆t/2 By putting values we get . 343×3/2 =514m. Another we put 343×5/2 =814m Combined we get . 514+814 =1328m Ok sir

[@BizzBooms]

1 - Yes, sound obeys the laws of reflection. Following are the laws: a -

[@reenadasif8843]

Best teacher ever

[@ManochaAcademy]

Thanks

[@sanjaymohanty4057]

Yah

[@goldeeshorts7036]

Sir question 3 samag nahi aaraha

[@goldeeshorts7036]

@@ManochaAcademy sir q no 3 samage me nahi aaraha hai

[@sambraniviishnnuvardanbabuu]

@@ManochaAcademy happy birthday manocha academy

[@bhaskardebnath324]

1. Yes, sound obey the laws of reflection, they are - The incident ray angle is equal to the reflected ray angle The normal, ray of incidence and ray of reflection all lie on the same plane 2. Our ears need some delay before the sound echo can be heard again, that's why in small spaces, as the sound echoes too quickly, it cannot be heard by the ears 3. 1st echo - T = 0.3s D = 2d S = 340m/s 340 = 2×10/3 D = 51m 2nd echo - D = 85m Total distance = 51+85 = 136m

[@amitabhabhattacharyya1759]

Sir... U explain us all concerned topics of Sound in a very lucid way n lively ...really praiseworthy.. Thanx a lot.. Regards 🙏

[@addictionforphysics8509]

Third question answer is 136 because The man standing between two heals and the man fire the bullet and the sound is reflected from both the hills then Distance traveled 2d at 0.3s Distance =speed * time 2d= 340 * 0.3=51 Distance =speed *time 2d=340*0.5=85 Add both distance 85+51=136🎉🎉

[@liibaanphysics8120]

Why do you use the speed 340m/s ?

[@addictionforphysics8509]

@@liibaanphysics8120 it is speed of sound

[@liibaanphysics8120]

Why don't you use 330m/s as speed of sound.

[@addictionforphysics8509]

@@liibaanphysics8120 340 m/s is the standard speed of sound. If your weight is 50kg and you are taking it 47kg then your answer will come wrong. So 340

[@DamilareJoseph234]

Yes,1)

[@all8nonechannelchannel.78]

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[@SylveliaIheshiulo]

You're right

[@roshnib1347]

1.yes,

[@vishwashn933]

8 years back If I would have got you like teacher, or these type of study material in my PUC I would have got distinction..... Although I worked hard I couldn't understand these silly topics.. but practically I understood everything now, although it may not help in my studies or career now... Thk u heartly teacher....

[@georgemichael2288]

Qn 01. YES it obey... Qn 02. For an echo to occur, it needs at least 17m from an obstacle to listener. Qn 03. The answer is 136 m, (I took velocity of sound in air as 340 m/s)

[@Clusterofnuerons]

yee6

[@quizforyou2574]

1)Yes, sound obey the law of reflection That is angle of incidence=angle of reflection. 2)room is a small place. The minimum time gap to hear echoes (0.1s). And in room curtains, carpets,and other objects absorb the sound. 3)1st hill=56m 2nd hill=85m So, distance between two hills=136m Thank you a lot sir❤️❤️❤️

[@FreezyRishabh]

56+85=141m

[@learnwithg.k.s.5481]

Excellent video Answers are 1. Yes,Laws of reflection of sound are a. Angle of incident of sound is equal to angle of reflection of sound. b. Normal,angle of reflection of Sound and angle of incident of Sound lie on the same plane. 2.We cannot hear the echoes in a small room because the area of a room must be large for echoes to be produced

[@metuselaonesmo5005]

sir I have loved your teaching style and the vivid examples that you give in your videos

[@ManochaAcademy]

Thanks a lot :)

[@santoshyadav-fe5nr]

@@ManochaAcademy FFS a good day today I was just thinking about right for me to do it for you to be with you and I have to do it for me and I don't know if you want to go to the store to get a new one for me to do it for you to know if you don't have a good day today and I have to be there in Sir John Salmond is wrong

[@maryalia6624]

1. Yes... the angle of incidence is equal to the angle of reflection and the incident Ray, the normal and the reflected Ray at the same point of incidence all lie on the same plane. 2. We can't hear Echoes in a small room because sound doesn't reflect back. 3. d=51m d=85m. Thank you sir. Your explanation was superb 👌👏👏👍

[@maryalia6624]

Then add up the distances=51+85=136m.😋🤗😇

[@yashstarkumar1801]

Ye 1:yes Laws of sound is Echoes and reverberation 2: To listen echones sound the area will be more then we listen .in small room we can't listen because its area will be less .. 3:Distance=speed*time 1st one =2d=340m/s*0.3s Then 2d=102 D=102/2 D=51m 2one =2d=340*0.5s Then 2d=170 D=170/2 D=85 Then1+2= 51+85 =136

[@exploringnature1151]

Echoes and reverberation are not the laws of sound and Qno 2 u can directly answer that there is no time gap or very very less

[@mamtapadhy118]

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[@RamRam-gs1so]

1: yes it does , incident rays = reflected rays 2: beacuse large distance help hear echoes (minimum distance between speaker n reflector should be more than 17 metres ) 3: 1- 51 2- 85( 51 +85=136) Distance between the two hills is 136

[@ManochaAcademy]

Q1 Correct. But you have to give the 2 laws of reflection that light has. Q2 Right! Also mention minimum time is 0.1s to hear echo. Q3 Correct answer :)

[@j.govardhanammaj.govardhan7171]

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[@asmamomin6922]

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[@ManochaAcademy]

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[@cedrickmabowa5071]

My best teacher,I'm corresponding student in South Africa and I rely on your videos to learn

[@vedparmar65]

Q-1) Yes, the laws of reflection of sound are as follow Incident rays go ang coming ray is reflected ray. Q-2) We cannot hear echoes in a small room because we hear an echo in a distance of 17 metres or more from the reflecting surface / an area because equal distance in the forward reverse is direction. Q-3) Distance = speed × time Therefore, A) 1st D = 340m/s × 0.3s = 102m B) 2nd D = 340m/s × 0.5s = 170 m Total D = 272m

[@josy26]

The total would be the total distance travelled by sound which is not the same as the distance between the two hills, that would be double. So you'd just have to divide it by 2.

[@rabbitkook937]

1.Yes and firstly there are 3 laws of reflection which are:- a. Angle of incidence = angle of reflection b. Incident ray, reflected ray and normal lie on same plane c. Incident ray and reflected ray are on the either side of normal 2. The distance of our ear and the wall is less than 17.2 m 3. 136 meter

[@harshithgowni1528]

1) Sound does obey the laws of reflection. The laws of reflection for sound is 1. The angle of incidence is equal to the angle of reflection. 2. The incident sound, reflected sound and normal all lie on the same plane. 2) We can't hear echoes in a small room because echoes need a minimum distance of 17m to produce an echo and a room has a much smaller distance than 17 metres. 3) 34m

[@ravirk7315]

U r done a good job 3question explanation

[@ravirk7315]

Time gap diff is 0.2 sec

[@ManochaAcademy]

@Harshi Gowni, Very good!! Q1 and Q2 answers are correct :) Q3, answer should be 136 m. For this question, draw a rough diagram of a man standing between two hills. Let the distance of one hill from the man be 'a' and other hill from man is 'b'. So total distance between to hills is 'a + b'. As discussed in video, for echo since sound travels twice the distance, formula is: 2d = speed x time, where d is the distance. Since it's not given in the sum, you can take speed of sound in air as 340 m/s (or any standard value that you use). Now consider each hill separately: For first time t1 = 0.3 s, we can do 2a = 340 x 0.3. So a = 51 m For 2nd time t2 = 0.5 s, we can do 2b = 340 x 0.5. So b = 85 m So total distance = a + b = 136 m. Let me know if it is clear now!

[@harshithgowni1528]

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[@ManochaAcademy]

Thank you :) Do share our videos with your friends and family!

[@emmyfunzamize]

I am from Nigeria I love ur teaching sir I wish I had a teacher like you here

[@kashinathkarmakar9552]

(Answer of Q1) Yes, sound obeys the laws of reflection. Laws of reflection of sound --- (i) Angle of incidence=angle of reflection. (ii) incident sound, reflected sound and the normal lie on the the same plane. (Answer of Q2) For hearing echoes, the minimum distance between the speaker and the reflecting surface should be 17m. In small rooms, the distance is less than 17m and hence, we cannot hear echoes in small rooms. (Answer of Q3) Distance=speed X time The distance between the man and the 1st hill=(340m/s X 0.3s)/2 =51m The distance between the man and the 2nd hill=(340m/s X .5s)/2 =85m So the total distance between the two hills=(51+85)m=136m.

[@AastabolProductions]

I'm doing sound engineering. Your videos are helping me a lot. Thank you sir ❤🙏

[@saudshaikh3679]

THANKS FOR YOUR EFFORT

[@ManochaAcademy]

Our pleasure!

[@Amuvlogs-h8h]

What is sound

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[@Dinesh7219]

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[@ManochaAcademy]

Thanks a lot :) Great to hear that you liked the video!! Very true, the audio visual aids are greatly enhancing the learning experience and making it more visual for the students today!

[@ankushgarg7714]

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he is 😀

[@legendsshorts_101]

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[@hazmatt0093]

Fantastic lesson. Strong explanations and examples that are easy to understand. My 8 year old was able to answer all of the questions correctly!

[@Sr-us6io]

1)it obeys and laws of reflection is the reflection of light is equal to angle of incidence. 2)it should be nearly 17m wide room to hear the sound of echo. 3)

[@jiviteshtutorials.....5597]

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[@MariaShikololo]

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[@ManochaAcademy]

Thanks for liking

[@rathorekuldeep5811]

1.yes, angle of incidence is equal to angle of reflection and angle I,angle r and normal lie I'm the same plane 2.Because reflecting surface is smaller than the wavelength of sound wave 3.136 m

[@ARJUNFFKING-wn4cw]

Sir. I love the way u are teaching i could understand everything ❤‍🔥❤‍🔥❤‍🔥

[@ManochaAcademy]

Thanks a ton

[@anshikajaiswal185]

1.yes..it obeys the law of reflection...

[@valentinoeditz9154]

Pls solve no 3

[@penguinzoneyt]

For anyone who requires the answer to the third question: To calculate echo distance, you'll require the general formula to calculate the distance of the echo, which is: "2d = s × t". Hence, we'll be required to do the following steps in order to calculate the echo distances: 1. Calculate the distance of first echo: 2d = 343 × 0.3 d = 102.9 / 2 d = 51.45 meters 2. Calculate the distance of second echo: 2d = 343 × 0.5 d = 171.5 / 2 d = 85.75 meters 3. Sum up the distances between two echos, to find the total distance: 85.75 + 51.45 = 137.2 meters. Hence, the distance between the two mountains would be 137.2 meters. Happy to Help !🤗

[@THV__JAANot7]

Thank you so much friend 😊😊

[@penguinzoneyt]

​@@THV__JAANot7😊

[@RohitJ-ej6xx]

Ans 1 Yes, it obeys the laws of reflection. Two laws of reflaction are a. Angle of incidence, reflaction and normal all lie in same plane. b. Angle of reflection is equal to angle of reflection i=r Àns2- we cannot hear the echo sound because of our lower sensitivity of ear and dur to less space. Ans 3- ....

[@THV__JAANot7]

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[@jyothirmaikodimadugu2093]

Sir your way of explanation was superb

[@karthisv9589]

Its very clear and perfect understanding sir. Thanks for sharing. 1) angle of incident ray = angle of reflection ray 2) because below 17m we cannot hear any echoes 3) 4d = 340 * 0.8 s = 68 m.

[@xqdrt]

3 is wrong

[@rajashreesarna9751]

Hi sir! This link was sent to us by our teacher before the exam. These videos really helped. thank you!!!!!

[@ManochaAcademy]

Glad it was helpful!

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[@abuhenamunna9398]

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[@punamsharma1734]

1.Yes the sound obeys the laws of reflection. First law-The angle of incidence is equal to the angle of reflection. Second law-the angle of incidence,the angle of reflection and the normal ray all lie in the same plane.

[@drramakrishnan55]

Hello sir. I don't lyk physics that much before watching your video. Thank you sir

[@ManochaAcademy]

Great to hear that you liked the video :) Do check out more videos at www.manochaacademy.com

[@knoz35]

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[@yasminotsmane7384]

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[@ManochaAcademy]

Happy to hear that video was helpful :) All the best for your test!!

[@ashishbabu6494]

Thanks for ur video sir...I really Loved it... Q1.yes,the law of reflection is the angle of the incident ray is equal to angle of reflected ray Q2.because ,the distance should atleast 17 m to hear the echo Q3.31 m

[@ManochaAcademy]

Happy to hear that you liked the video! Thanks :) Do check out more videos at www.manochaacademy.com Q1 and Q2 are correct! Q1 you can also write the 2nd law: incident sound, reflected sound and the normal all lie on the same plane. Q3, answer should be 136 m. Here is the solution: For this question, draw a rough diagram of a man standing between two hills. Let the distance of one hill from the man be 'a' and other hill from man is 'b'. So total distance between to hills is 'a + b'. As discussed in video, for echo since sound travels twice the distance, formula is: 2d = speed x time, where d is the distance. Since it's not given in the sum, you can take speed of sound in air as 340 m/s (or any standard value that you use). Now consider each hill separately: For first time t1 = 0.3 s, we can do 2a = 340 x 0.3. So a = 51 m For 2nd time t2 = 0.5 s, we can do 2b = 340 x 0.5. So b = 85 m So total distance = a + b = 136 m. Let me know if it is clear now!

[@lekshmipriya2467]

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[@ManochaAcademy]

It's my pleasure

[@breshamasters8613]

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[@_Anjalithisside_]

Amazing teacher with amazing topic

[@nikitha6550]

Q1: yes , sound obey laws of reflection Reflection of sound -insident ray ,it's carrospoing reflected and the normal lay on the same plane Q2: we cannot hear eho in a small room because there are good absorbers of sound . And echo is possible in large area where it contains the reflector of sound

[@funnymemes924]

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[@ManochaAcademy]

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[@hasini.s2010]

Q1: yes,

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[@divyanshgupta8036]

A2: we cannot hear echoes in a small room because the room is so small and time taken by sound to get reflected and reach our ear is less than 0.1 seconds so our ears are not so sensitive to hear it

[@MaheshKumar-fe8fm]

1. The angle of incident=angle of reflection 2. Because their very little distance 3. First hill distance is 102. And second hill distance is 170 Total is 272.. Sir please check it and reply

[@ujjalbaraily9671]

U r a really very good teacher

[@ManochaAcademy]

It's my pleasure

[@methukihesansa]

1. yes, the angle of incident sound and the reflected sound is equal. the point of sound, incident sound and the reflected sound lies on the same plane. 2. when the obstacle is too close, the echo is not clear 3. ( I feel board to solve sums...)

[@JugulkishorGupta]

Bored!!

[@dericksworld4092]

Thanks for this class

[@ManochaAcademy]

You are welcome

[@wewilllearn1976]

1.ans -Yes sound is obey the law of reflection... 2. ans- we cannot hear echoes in small room because it's need a large area to reflected the sound wave. 3.ans- 2distance =velocity ×time

[@sayanbiswas7021]

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[@ManochaAcademy]

Most welcome!

[@sarabdeepsinghsartaj4503]

Sir second answer is: Because of room size, it is small to the sound travels short distance

[@nnamdimarcel4556]

Please Sir, help me with the solution to the question below: The speed of sound in air is 330ms-1. How far from the centre of a storm is an observer who hears a thunder clap 2s after the lightning flash? (Neglect the time taken by light to travel to the observer)

[@marty9019]

The speed of sound in air is 330ms-1. This means that 1 second represents 330m. Now, in the question it says that it takes 2s for the sound to travel from the centre of the storm to the observer this means that the distance at which the oobserver is standing is 330m x 2s. Now here you can remove the units of those values to make it a little less complicated. Acoording to all this your answer I think should be 660m. Hope it helps! Goodluck!

[@avrrockstar5923]

sir 3rd answer is distance=speed.time so, 4d=340m/s x 0.8=272m so d=68m

[@gymlover1617]

Good teaching method .adorable .nice

[@ManochaAcademy]

Many many thanks

[@pranavsharma7207]

1)angle of incidence = angle of reflection 2)minimum distance needed is 17 meters

[@jaanvidesai4417]

The explanation was so nice i liked the video so much and i learned this without any doubt From Taanvi Desai

[@ManochaAcademy]

Thanks a lot 😊

[@mahmudadam7214]

Q1. It obeys The angle of incidence is equal to the angle of reflection Q2. Because there's no enough distance to reflect the sound

[@vedanthgovindan5824]

00:05 This video is about the reflection of sound. 01:40 Sound reflection follows similar laws as light. 03:21 Reflection of sound leads to echo and reverberation. 05:01 Understanding sound reflection in large spaces 06:44 Hill absorbs sound energy resulting in softer second hello. 08:24 Reverberation is the persistence of sound caused by overlapping reflections. 10:04 Balance between sound absorption and reverberation in acoustic engineering 11:39 Absorbers reduce sound reflection in the house

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Thanks and welcome

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It's ok

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Or any other country

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[@ManochaAcademy]

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You are welcome

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[@chiomaeverista6031]

1- YES CAUSE I = r 2- cause the distance is not up 17m nor the time it will won’t be up to 0.1sec 351+85 = 136m

[@sarikabalse6724]

351 + 85 is 436

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You are most welcome

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[@afekiluovivian1374]

1.yes it obeys the law of reflection and it states that the incident ray, reflected ray and normal all lie on the same plane.2.because of the room is small and the wall, curtains and ceiling does not give the sound chance to escape and we can hear echo in a larger place.3. the distance between the two hills is 132m.

[@kiransaleem9856]

@monach academy i want to understand refraction of sound... im. not finding ur video on this topic.

[@sarojashetty6224]

1.Incident ray ,reflected ray and the normal always lies on same plane Secand law:angle of incidence is equals to angle of reflection. 2.in small room does not reflect. 3.799m ....Thank u sir..this vedio very much helps to me